Speech Enhancement and Recognition in Car Environment Using Blind Source Separation and Subband Elimination Processing

We propose a new algorithm for blind source separation (BSS), in which independent component analysis (ICA) and beamforming are combined to resolve the low-convergence problem through optimization in ICA. The proposed method consists of the following four parts: (1) frequency-domain ICA with direction-of-arrival (DOA) estimation, (2) null beamforming based on the estimated DOA, (3) diversity of (1) and (2) in both iteration and frequency domain, and (4) subband elimination (SBE) based on the independence among the separated signals. The temporal alternation between ICA and beamforming can realize fastand high-convergence optimization. Also SBE enforcedly eliminates the subband components in which the separation could not be performed well. The experiment in a real car environment reveals that the proposed method can improve the qualities of the separated speech and word recognition rates for both directional and diffusive noises.